。
No news is good news.
Literal
Letter [subject-が] not-have [topic-のは] good news.
A compact variant of the proverb using 知らせ (news/tidings) instead of 便り for the predicate. The zero copula at the end — stating 良い知らせ without だ or です — gives it the crisp, aphoristic quality typical of proverbs.